Blue Sea Systems Mini Automatic Charging Relay M-ACR 7601 — 12/24V 65A with Start Isolation

The Blue Sea Systems 7601 Mini Automatic Charging Relay (M-ACR) automatically combines and isolates 12/24V battery banks up to 65 amps while protecting electronics during engine starting.

The M-ACR 7601 is a compact automatic charging relay engineered to manage alternator output on small to medium marine engines. It senses charging voltage and connects or isolates the start and house battery banks without manual switches, supporting both 12V and 24V systems. With Start Isolation (SI) logic, it guards sensitive house loads from voltage dips and spikes during engine cranking, and its small footprint allows surface, rear, or panel mounting.

How does the M-ACR simplify battery charging on boats?

The M-ACR automatically links the starter and house batteries when an alternator is charging, then separates them when charging stops. This removes the need for manual battery management and ensures charging current is distributed where it’s needed without operator action.

• Automatically senses voltage and engages at charging thresholds
• Combines banks for charging, isolates when engine is off
• Supports alternator currents up to 65 A for common outboards and inboards
• Works in both 12V and 24V electrical systems

What protection does Start Isolation (SI) provide during engine cranking?

Start Isolation temporarily separates the house circuits from the starter battery while the engine cranks, preventing voltage sags and spikes from reaching sensitive electronics. This reduces the risk of resets or damage to navigation, audio, and communications equipment caused by transient voltage events.

• Isolates house loads during engine start to maintain stable electronics
• Prevents large inrush currents from pulling down house voltage
• Automatically reconnects banks after cranking completes
• No manual intervention required—logic is built into the unit

Where and how can the M-ACR 7601 be mounted and connected?

The M-ACR’s compact form factor lets you choose surface, rear, or panel mounting to best fit cramped engine compartments or control panels. Terminals are sized and arranged for typical marine battery cabling, and the unit is designed to be installed close to the battery banks it controls for efficient circuit routing.

• Three mounting orientations: surface, rear, or panel
• Small footprint is ideal for tight engine-room spaces or dash panels
• Terminals accommodate standard marine battery cable sizes
• Made in the United States to marine electrical standards

What are the electrical and physical specifications I should know?

The M-ACR handles up to 65 amps of alternator charging current and is suitable for both 12V and 24V installations. The compact packaged dimensions and lightweight design simplify installation on a variety of vessels and integration into Blue Sea's Custom 360 panels when a module is preferred.

• Rated for alternator currents up to 65 A
• Compatible with 12V and 24V DC systems
• Package dimensions approximately 17.0 x 9.4 x 7.9 cm and 0.55 lb weight
• Also available as a module for Custom 360 Panels

Who is this product for? The Blue Sea Systems M-ACR 7601 is designed for boat owners, marine electricians, and fleet managers who want automated battery charging control and protection of onboard electronics. It’s an excellent choice for vessels with outboard engines or smaller inboards that produce charging currents under 65 amps and for anyone seeking a compact, easy-to-install relay with Start Isolation logic. Installers who value flexible mounting and integration with Blue Sea Custom 360 panels will find this relay particularly convenient.